Water-tube bridge-wall baffle for steam boilers



1 28 1927. 9 E. J. FRANKLIN WATER TUBE BRIDGE WALL BAFFLE FOR STEAM BOILERS ATTORNEY.

ed July '7 1925 3 Sheets-Sheet 1 INVENTOR. [a waro/ Frank/in flhn n/ 28 1927. June E. J. FRANKLIN WATER TUBE BRIDGE WALL BAFFLE FOR STEAM BOILERS Filed July! 1925 s Sheets$heet 2 Wwi.

INVENTOR.

- [a l yard Frank/01 BY W Mn fi v ATTORNEY.

June 28 1927.

1,634,139 E. J. FRANKLIN WATER TUBE BRIDGE WALL BAFFLE FOR STEAM BOILERS 5 Sheets-Sheet 3 Filed Ju1y'7. 1925 fa wara J Franfi/l'n av/232M ,0 A4

A TTORNE Y.

Fatented Jame 23, 1927.

UNITED STATES tiilla PATENT OFFICE.

EDWARD J. FRANKLIN, 0F SALT LAKE CITY, UTAH.

WATEETUBE BRIDGE-WALL BAFIFLE FOR STEAM BOILERS.

Application filed July 7, 1925. Serial No. 41.963.

This invention relates to a bridge wallboiler therein shown comprises a-series or battle for steam boilers of the water tube type and the main objects of the lnvention are:

To expose a greater tube surface to the radiant heatof the furnace.

To eliminate the necessity of a fire brick bridge wall.

To provide maximum combustion space with given boiler setting dimensions.

To provide a more suitable pocket or chamber for the collection and easy disposal of ash, flue dust or soot which may collect from the back passes.

To increase the circulation of water in the lower row of tubes and, thus prevent deposition of scale or sediment with the result ant failure of tubes.

To protect the furnace brick work both by direct screening effect of back and side walls and by reducing the heat in the combustion chamber.

To reduce furnace maintenance costs by, eliminating large fire brick bridge walls commonly in use, and by reducing furnace temperatures due to increased radiant heating surface exposed to combustion chamber.

Theinvention is particularly applicable to the straight tube type of boilers such as the Heine, Babcock, and Wilcox, Edgemoor and Casey-Hedges steam boilers but is also applicable with certain modifications to other types of water tubes such as the bent tube boilers of Stirling or similar types.

The acompanying drawings illustrate embodiments of my invention and referring thereto:

Fig. 1 is a longitudinal section of a straight tube boiler provided with my improved, water tube bridge wall bafiie.

Fig. 2 is a section on line 2-2 in Fig. 1, with part of the front header broken away.

Fig. 3 is a section on line 3+3 in Fig. '1.

Fig. 4 is a section on line -4-4 in Fig. 1.

Fig. 5 is a view similar to Fig. 1 showing the application of the invention to a straight tube boiler of a somewhat different construction.

Fig. 6 is a partial section showing a different location of the water circulating system for the lower row of tubes.

Fig. 7 is a longitudinalsection of a bent tube boiler provided with a bridge wall bafiie according to my invention.

Fig. 8 is a section on line 88 in Fig. 7.

Referring to Figs. 1 and 2 the steam bank of water tubes 1 connected to forward and rear headers 2 and 3 which are also connected to the steam drums 4. The usual means are provided for drawing off steam from the steam drum and for supplying water to the boiler. The boiler is located over a fire-box or combustion chamber 6 which may be provided with .any suitable means for firing the same, for example, an oil burner 7, and with suitable means for the admission and regulation of air supplied for combustion. A stack outlet 8 is provided at the upper rear portion of the boiler setting, and battles 9 and 10 of suitable refractory construction are arranged in such manner as to intercept the gas passing from the fire-box to the stack and deflect such gas so as to cause same to pass several times between the water tubes in well-known manner. The bafiie plate 10 may be arranged in accordance with the usual practice, preferably inclined or obliquely extending from nearly the top of the water tubes to the bottom thereof in a downward and rearward direction and according to my invention a supplementary or additional baflie means 16 is provided preferably in line with this bafiie plate 10 and formed of suitable refractory material supported and protected by water tubes as hereinafter described.

In applying my invention to a boiler of the straight tube type I prefer to bend the lower row of tubes indicated at 1 downwardly where the approach the inclined baffle plate 10 an to extend said tubes in oblique downward direction to the rear end of the fire-box. Said downwardly bent portions may extendat any suitable angle, for example at an angle of from 30 to 75 to the horizontal. In the form shown the rear portions of these tubes are bent at an angle of approximately 45 to their front portions .and to the remaining tubes. As shown in the drawings, said boiler tubes 1' may extend through the rear wall of the fire box and be connected to a lower header 12 out side and immediately ad'acent the rear wall 19 of the furnace. Sai lower header may be connected at its ends by pipes 13 extending either inside or outside of the furnace walls to an upper header 14 which is connected by pipes 15 to the rear header or water leg 3 i of the steam boiler. Bafile means 16 consisting for example of plates or slabs of refractory material indicated at 17 are arranged.- back of and overlying the oblique ortions of water tubes 1 so that said ba e means are supported by such water tubes and are protected by the water tubes to a large extent from the heat of the combustion chamber. The upper and lower header 14: and 12 may be provided with 'l s 18 where they are connected to the pipes 13 to facilitate cleaning of these headers, the outer opening of said Ts being plugged in normal operation. Suitable blow-oil means 40 may also be provided at the ends of the lower header.

llhe bafie wall 16 cooperates with the rear wall 19 of the furnace to form pocket 20 for the collection of ashes, soot, dust, etc, from the back passes, and a suitable opening 21 and door 22 may be provided for permitting access to said pocket for removal of collected material therefrom.

The construction or the boiler shown in Fig. 5 is substantially the same as that above described with the exception that drum 4 is located at the rear of the boiler setting; and extends transversely with respect to the tubes and is connected to the front header 2 by means of pipes 23. l have also shown the short pipes 15 connecting the header let- '0 the Water leg 3 as being bent at right angles in this case although either the straight or bent form of connecting pipe is adaptable to either type of boiler construction.

In the operation ofthe boilers above described fuel and air are admitted through burner means 7 and combustion takes place in the combustion chamber 6. It may be noted that by forming the bridge wall baille as substantially a continuation of the baille 10 and carrying it downwardly and rearwardly a larger combustion chamber is provided than is the case in the usual type of construction in which a tire brick bridge wall is provided extending vertically downward from the lower end oi battle 10 that approximately from the position of the I upper end of the bridge wall bat-lie 16 of my invention. By means of my improved con struction a substantially unobstructed coinbustion chamber is irovided extending from the front wall ll 0 the furnace to the rear Wall 19. The provision of such. a large unobstructed combustion chamber is of particular advantage in connection with the burning of liquid, gaseous, or powdered fuel. as it permits more complete combustion of such fuel therein. The hot products of coinbustion pass up over the upper edge of hams 10, down between bellies l0 and 9. and thence out to the stack outlet 8, giving up their heat to the Water tubes in their passage to heat the water therein. The lower row of tubes 1' are exposed to the most intense heat and particularly the inclined por tions thereof in front of the bafie 16. In

addition to heat received directly from the hot gases, these tubes are exposed to radia tion of heat from the hot walls of the cornbustion chamber and also take up heat received by radiation onto the battle 16 with which such tubes are in contact at their inclined portions. The rapid heating of the water thus produced in these tubes causes an extremely good circulation of water therein and not only produces an eliicient utilization of the heat but also prevents deposition of the scale or sediment in the tubes. The direction of circulation of water is downward in the connecting pipes 13 and upward in the tubes 1.

The reception of a considerable amount of heat by radiation onto these tubes cools the combustion chamber somewhat below the temperature produced in the ordinary type of boiler in which the combustion chamber is almost entirel surrounded by fire brick and thus protec's the furnace brick work. Furthermore the inclined portions of the tubes 1 serve to protect the brick or refractory plates 17 both by direct screening action and by taking up heat therefrom. In addition to the above advantageous features the elimination of the lire brick bridge wall now used in itself materially reduces the cost of maintenance of thefurnace.

Any soot, dust, or ashes collecting above the baffle 10 or the bridge wall bafile it settles to the bottom of pocket 20 and may be easily removed from time to time by removing door 22 and cleaning out the collected material through the opening 21. In the ordinary type of water tube boiler any solid material deposited in the back pass-es collects between the tubes and is very difiicultly removed. By providing the lower-most row of tubes, according to my invention, with p rtions extending clear of and below the other tubes and providing a wall of refractorymaterial on such portions of these tubes a readily accessible and easily cleaned pocket is provided between said wall of fractory material and the rear wall of the furnace, into which such deposited solid material falls and from which it may be removed easily.

While l prefer, for the sake of convenience andsupcrior construction, to locate the lower header 12 outside the rear wall of the furnace as above described, it may in some cases be located inside, but immediately adjacent the rear wall, as shown in Fig. 6. In such case the lower tubes 1' do not extend through the rear wall but header 12 extends through the side walls for connection to pipes 13. In order to facilitate the cleaning a metal plate 24 may be provided over the header 12.

As shown in Figs. 7 and 8 the bridge wall bathe according to my invention may also be applied in connection with boilers of the bent lllb Cir:

llt;

tube type such as the Stirling boiler. The boiler shown in these figures comprises the usual steam, water and mud drums 25, 26, 27, and 28 connected in the usual manner by banks of tubes indicated at 29, 30, 31, 32, and 33, and provided with the usual means for feeding water, thereto and permitting withdrawal of steam therefrom. Bafile means of suitable refractory material may also be provided arranged in any suitable manner for example as indicated at 34, 35, 36, 37, and 38, so as to cause the hot combustion gases to pass between the tubes in a circulatory manner, to the stack outlet 8.

According to my invention the lower row of tubes 29 of the front bank of tubes 29 are 1 continued on down below the lower drum 28 and extend downwardly and rearwardly to a lower header 12 located outside the furnace wall. The portion of the tubes 29' below the drum 28 may as shown be in a direct line with the upper portions of these tubes or they may if desired be bent at any suitable angle to such upper portions in order to provide the desired slope, say from 30 to 75 to the horizontal. A bridge wall baflle 16 comprising for example refractory slabs,

"plates, or bricks 17 is provided as before,

above and supported b the lower portions of these tubes so as to direct the combustion gases upward and eliminate the necessity for the usual fire brick bridge wall extending vertically downward from drum 28. The lower header 12 is connected as before at its ends by means of pipes 13 to the upper header 14 which is connected by short pi cs 15 to the drum 28. It will also be seen t at as before an unobstructed combustion chamber is provided extending between the front and rear walls of the furnace, and the baffle 16 cooperates with the rear furnace wall 19 to form a pocket 20 for the collection of I soot, dust and ashes, and opening 21 and door 22 are provided for the removal of such collected material. The manner of operation of this type of boiler is well understood, including the direction of flow of the hot combustion gases therethrough, and the manner of operation and advantageous features of my invention are substantially the same in this case as in the forms above described.

The invention comprises in any case a row of tubes located below or constituting the lower-most row of a bank of water tubes and having inclined portions extending rearwardlyand downwardly, preferably at an 0 angle of between 30 and75 to the horizontal, from aposition above the combustion chamber to a position at the rear of the combustion chamber and preferably outside the rear wall of the furnace, and inclined bafile means consisting of refractor material located'above and supported y, and preferably in direct contact with said inclined portions of these tubes, said inclined portions being thus adapted to receive heat bank, and in such a position that a pocket is provided above and behind said baflie means, for the collection and easy removal of deposited solid material. Also, in all the constructions shown, a large and unobstructed combustion chamber is provided between the front and rear furnace Walls, so as to provide ample space below the .tubes for the complete combustion of liquid, gaseous, or

powdered fuels.

What I claim:

l. Ina water tube boiler, in combination with a furnace having a combustion chamber, a bank of water tubes above said combustion chamber and connected for circulation of water therethrough, the lowermost row of said tubes having their rear end portions inclined downwardly and rearwardly to a position adjacent the rear wall of the furnace and in such position as to be clear of the remaining tubes of said bank, means connecting the rear ends of said lowermost row of tubes to the water circulating system, inclined refractory bafile means supported upon said inclined portions of said tubes and cooperating with the rear wall of the furnace to form a ocket below said remaining tubes for col ection of solid material, and normally closed opening means in the wall of the furnace for permitting access to said pocket. 2. In a water tube boiler, in combination with a furnace having a combustion chamber, a bank of inclined water tubes above said combustion chamber and connected for circulation of water therethrough, the lowermost row of said tubes having their rear end portions bent so as to be inclined downwardly at a greater angle to the horizontal than the remaining tubes and said inclinedportions extendin from a position intermediate the ends 0 the bank of tubes to a position immediatel adjacent the rear wall of the furnace, ba e means of refractory material located above and supported upon said inclined ortions of said tubes and cooperatin wit the rear wall of the furnace to provi e a downwardly converging pocket for collection of solid material, and normally closed opening means in said rear wall for permittingfaccess to saidpocket.

3. In a bollerfurnace, a front wall, a rear wall, asubstantially unobstructed combustion chamber extendin between said front and rear walls, a ban of water tubes extending above said combustion chamber,

the rear portion of the lowermost row of said tubes extending obliquely downwardly to the rear wall, a baille of refractory material supported on said rear portions of said lowermost row of tubes and extending upwardly and forwardly from said rear wall to a position above the combustion chamber and cooperating with the rear wall of the furnace to provide a downwardly converging pocket for -collection of solid material, and means in said rear wall for permitting access to said pocket.

4. In a boiler furnace a front Wall, a rear wall a substantiallv unobstructed combus tion chamber exten ing between said front and rear walls a bank of inclined water tubes extending above said chamber, the tubes in the lowermost row of said bank having their rear portions bent so as to be inclined downwardiy to the rear at a greater angle than the remaining tubes, said bent portions exeeaise tending from a position intermediate the ends of a bank of tubes to a position immediately adjacent to the rear wall of the furnace, refractory baffle means supported on said bent portions and extending upwardly and forwardly from said rear wall so as to form a part of the Wall of the combustion chamber and to direct the combustion products therefrom into contact with the forward portions of said bank of water tubes and to also cooperate with the rear Wall of the furnace to provide a downwardly converging pocket above said battle means for collection. of solid materiahand means in said rear wall of the furnace for permitting access to said pocket.

In testimony whereof I have hereunto subscribed my name this 30th day of June, 1925.

EDWARD J. FRANKLIN. 

